Method for controlling microturbulence

Abstract

A method for controlling microturbulence in a medium flowing near a surfaces disclosed. The method includes the steps of measuring the forces acting near or on the surface and using those measurements to determine the state probabilities for the microturbulent events occurring at the surface. The control method then activates selective cells in an array of cells to apply forces at the surface to counteract the microturbulent events and thus reduce turbulence. Each cell has a pair of electrodes and opposing magnetic poles such that when the control method activates a cell, the interaction of the electric field and the magnetic field at the cell creates a Lorentz force normal to the surface.

What is claimed is: 
     
       1. A method for controlling microturbulence within a medium at a surface exposed to the medium, the microturbulence resulting from the action of microturbulent events at the surface, the method comprising the steps of: experimentally determining arrival rates for microturbulent low-speed streak events, microturbulent sweep events, microturbulent ejection events and microturbulent burst events;   determining limiting state probabilities for the microturbulent events using the relationship ##EQU6## where p l , p s  and p e  are the limiting state probabilities for the microturbulent low-speed streak events, the microturbulent sweep events and the microturbulent ejection events, respectively, and where μ l , μ s , μ e  and μ b  are the experimentally determined arrival rates for the microturbulent low-speed streak events, the microturbulent sweep events, the microturbulent ejection events and the microturbulent burst events, respectively;   measuring flow characteristics of the medium;   estimating discrete state probabilities of microturbulent events based on the limiting state probabilities, the measured flow characteristics and the relationship ##EQU7##  applying force in opposition to the microturbulent events at points on the surface and at times, as indicated by the discrete probabilities, that will reduce the microturbulence resulting from the action of the microturbulent events.   
     
     
       2. The method of claim 1 wherein the experimentally determining step further comprises the steps of: obtaining a series of values of the flow characteristics of the medium;   generating probability density function histograms and spectra of the characteristics based on the series of values obtained; and   calculating microturbulent event parameters associated with the flow characteristics, the parameters being used to experimentally determine the arrival rates.   
     
     
       3. The method of claim 2 wherein said parameter calculating step further comprises the steps of: determining a mean time between microturbulent burst events, a duration of the microturbulent burst events and a spacing of the microturbulent burst events; and   determining fractional time durations for microturbulent liftup events, microturbulent streak events and microturbulent sweep events.   
     
     
       4. The method of claim 1 wherein the limiting state probabilities determining step further comprises storing the limiting state probabilities. 
     
     
       5. The method of claim 4 wherein the experimentally determining step, the limiting state probabilities determining step and the storing step are performed iteratively until a predetermined accuracy measure is reached. 
     
     
       6. The method of claim 5 wherein the storing step further comprises: obtaining an average of the iteratively stored limiting state probabilities; and   storing the average as the limiting state probabilities for use in the discrete probabilities estimating step.   
     
     
       7. The method of claim 1 wherein the force applying step further comprises: applying a force normal to and away from the surface when the discrete state probabilities indicate a microturbulent sweep event is imminent;   applying a force normal to and towards the surface when the discrete state probabilities indicate a microturbulent liftup event; and   returning to the flow characteristic measuring step without applying a force when the discrete state probabilities indicate a microturbulent ejection event has occurred.   
     
     
       8. The method of claim 1 wherein the experimentally determining step, the limiting state probabilities determining step, the discrete state probabilities estimating step and the force applying step are performed iteratively to provide continuous microturbulence control.